Process and apparatus for dehydrating petroleum emulsions



F. W. HARRlS. PROCESS AND APPARATUS FOR DEHYDRATING PETROLEUM EMULSIONSAPPLICATION FILED FEB. 6, 191a. RENEWED JUNE 28. 1921.

1,405,129. Patented Jan. 31, 1922.

2 SHEETS-SHEET l.

F. W. HARRIS.'

PROCESS AND APPARATUS FOR DEHYDRATING PETROLEUM EMULSIONS.

APPLICATION FILED FEB. 6, 1918. RENEWED JUNE 23, I921.-

[nae/1% r fbrd iffirzs f UNITED STATES PATENT. OFFICE.

FORD w. HARRIS, oF Los ANGELES, CALIFORNIA, ASSIGNOR, BY MESNE ASSIGN-MENTS, TO PETROLEUM RECTIFYING COMPANY, OF sA FRANCIsCo, CALI- FoRNIA, ACORPORATION OF CALIFORNIA.

PROCESS AND APPARATUS FOR DEHYERATING PETROLEUM EMULSIONS.

Specification of Letters Patent.

Patented Jan. 31, 1922.

Application filed February 6, 1918, Serial No. 215,717. Renewed June 28,1921. Serial No. 481,171.

I To all whom it may concern:

Beit known that I, FORD W. HARRIS, a citizen of the United States,residing at Los Angeles, in the county of Los Angeles and State ofCalifornia, have invented a new and useful Process and Apparatus forDehydrating Petroleum Emulsions, of which :the followingis aspecification.

Myinvention relates to the artof separating water from petroleum oilwith which it is commonly found associated in the form to the action ofan electric current that the small water particles agglomerate intolarge masses of free water and that said largo masses may be readilyseparated from the oil by gravit In practicing the art of electricaldehydration it is found that on very heavy oils, for example oils offrom nine to sixteen degrees Baum and indeed on even lighter oils thatit is desirable and in some cases necessary to heat the oil for thepurpose of assisting in the coalescence of the water globules under theaction of the electric current and for the further purpose of expeditingthe separation of the large masses of free water from the body of theoil. In all forms of electrical dehydrators with Which I am familiar theoil, while being subjected to the electric current, is carried in openvessels in which the treating electrodes are suspended. As aconsequence, if the oil is heated to a degree best suited to theelectrical treatment, the light vapors'are driven off into the outer airwith a consequent loss of values. More important, however, the lightvapors mix with air in the top of the open vessel forming highlyexplosive and inflammable mixtures.

During the passage of the electric current through most emulsions aportion of the oil is vaporized and the vapors so produced rise into thespace in the top of thevessel and help form the inflammable mixtureabove referred to. Asthe vapors produced by the passage of the currentare often very hot I they may be hot enough to ignite when they reachthe-top of the-containing vessel or a stray electric discharge mayignite them. When ignited they cause an explosion and it is common inplants of this nature to have I dangerous and disastrous fires andexplos- 1011s.

The objects of my invention are as follows First: to provide a processand apparatus in which the emulsion, while being subjected to the actionof the electric current, may be heated considerably above the boilingpoint of the lighter constituents thereof without danger of fire.

Second: to provide means for holding the emulsion under considerablepressure during its electrical treatment so that the formation orvaporization of light vaporsis retarded or entirely prevented.

Third: to provide means for setting up and maintaining intensifiedelectric fields and for insuring the passage of the emulsiontherethrough.

Fourth: to provide means for preventing the accumulation of free watermasses in these fields.

Fifth: to provide means for regulating the character of the mixturebeing treated regardless of the character of the emulsion being treated.

Further objects and advantages will be set forth further hereinafter,

Referring to the drawings, which are for illustrative purposes only,

Fig. 1 is a side elevation, largely diagrammatic, of an apparatusadapted to carry on my invention.

Fig. 2 is a plan of the same, the electrical features being partlyomitted.

Fig. 3 is a side elevation of a treater, a portion of the shell beingpartly broken away and shown in central section for the purpose ofbetter illustrating my invention.

Fig. 4 is a section on a plane indicated by the line 44 of Fig. 3.

Fi 5 is a section on a the llne 55 of Fig. 3.

Fig. 6 is a side elevation, partly in section, of a preferred form ofheater.

'ig. is a section on a plane indicated by the line 7--7 of Fig. 6.

The apparatus shown in Fig. 1 consists broadly of a supply tank 11, asupply pump 12, a heater 13, a treater or dehydrator 14.,

sion 1n through a pipe 21 and forcing it through a pipe 22 and a valve23 into the heater 13. The pipe 22 passes upwardly and over the heater13 being connected into the top thereof. A stand pipe 24 is connectedinto the pipe 22, the upper end of the pipe'24 being open. The object ofthis arrangement is to prevent the heater 13 and the treater 14 frombeing drained by aback flow through the pipe 22 in the event of a leakof other opening developing in such a manner as to allow such a flow. Bycarrying the pipe 22 to a higher levelthan the top of the heater 13 andthe treater 14 and venting the highest point in the pipe 22 to the airthrough the pipe 24, the pipe 22 below the point of connection to thepipe 24 can be entirely emptied without siphoning liquid from the heater13. Also if the pump 12 for any reason is pumping air this air flowsupwardly and escapes from the end of the pipe 24 which is suflicientlylong to provide a static head which will balance the highest pressure inheater 13. It is extremely important to keep air out .of the treater 14and by making the outlet pipe 56 and the inlet pipe 22 connect into theextreme top of the treater 14 and the heater 13 respectively and byventing both to the air, the first through the tank 15, and the latterthrough the pipe 24, the draining of the heater 13 and treater 14 isprevented. Allso by providing the pipe 24 the inadvertent introductionof air to the treater 14 is prevented. By absolutely excluding air fromthe apparatus an explosion, due to the ignition of hot gases in thetreater, is ren- 'dered impossible.

The heater 13 may be of any of a large number of forms, that shownconsisting of a tight shell 25 having a head 26 through i which a steaminlet pipe 27 and a steam outlet pipe 28 pass, these pipes beingconnected to either end of a heating coil 29 inside the shell. Theemulsion delivered by the .pipe 22 passes through the shell 25 ininitimate contact with the heating coil 29. The heated emulsion isdelivered by a pipe 30 from the heater 13 to the treater 14.

The treater 14 consists of a tight shell 31 having a removable head 32.at one end.

Secured in gas tight relationship in the top of the shell 31 is aplurality of porcelain insulators. Each of the insulators shown in Fig.5 consists of a central core 33 of porcelain to which is cemented one ormore porcelain petticoats 34. The core 33 has a central flange 35 whichis clamped between a ring 36 and a series of clamps 37, the flange 35resting on elastic packing so that it makes a gas tight joint with thering 36. A central conducting rod 38 passes through the center of thecore 33 being threaded into a metal cap 39 cemented to the top of theinsulator, the rod 38 being cemented into the core 33 so as to form agas tight joint able bolts to a casting 43 secured to the top of theshell 31.

Coacting with each of the live electrodes 42 is a grounded electrode 50.Each of these consists of a plate of material cut away so that the lowerportion of the live electrode 42 is surrounded by the edge of the plate,the distance between the edge of the plate 50 and the live electrode 42being increased as the plate flares away in passing upwardly as shown inFig. 5. The plates or grounded electrodes 50 are in the same plane asthe live electrodes 42.

Equally distant between the plates 50 and on either side thereof arediversion plates 51, the plates having an emulsion opening 52 at thebottom thereof and a gas opening 53 at the top thereof. A diversionplate 51 is best shown in Fig. 4. The plates 50 and 51 fit snugly insidethe shell 31 and are spaced apart by bolts 54. It will be seen that thelive electrodes 42 and their supporting parts can be lifted out byunbolting the rings 36 from the casting 43 and that the plates 50 and 51can then be removed as a unit from the shell 31 by removing the head 32.

A flange 55 is secured in the top of the shell 31 and a pipe 56 issecured therein, this pipe extending very nearly to the bottom of theshell 31 and having one or more gas holes 57 therein inst inside the topof the shell 31 as best shown in Fig. 3. A valve 58 is provided in thepipe 56 which discharges into the settling tank 15.

The settling tank15 has a dry oil outlet pipe 60 near its top, a wateroutlet pipe 61 connected into its bottom and a circulating pipe 62connected into an intermediate portion of the tank 15. The pipe 62connects into the suction side of the circulating pump 16 which mayconveniently be a centrifugal pump driven by a direct connected motor63. A valve 64 is placed in a pipe 65 which connects the discharge sideof the pump 16 with the pipe 22 between the valve 23 and the heater 13.The steam pipe 27 may pass to a thermostatic valve 66 controlled by athermostat 67 in the tank 15.

The electrical means 17 may well consist of a plurality of transformerseach having a low tension primary 70 and a high tension secondary 71.One terminal of each of the secondaries 71 is connected to a ground wire72 which in turn is connected to the shell 31 and the other terminal ofeach of the secondaries 71 is connected through a wire 73 with one ofthe caps 39 and through its rod 38 with one of the live electrodes 42. Ifind it convenient to connect all of the primaries 70 in a single seriesand to control the maximum current therethrough by an adjustableimpedance 74. The primaries 70 may be'protected by fuses 75 andconnected to any suitable source of electric current through a switch76. In practice I prefer to impress a potential of 11,000 volts betweenthe electrodes 42 and 50 and an alternating potential of 440 volts is aconvenient voltage to supply to the switch 76. The deflector disc40serves to force hot gases away from the core 33 and thus preventflashovers thereon.

The method .of operation of my invention is as follows:

The emulsion to be treated is delivered to the pipe 21 and forced by thepump 12 through the pipe 22 into the heater 13, the

- end of the shell 31. The

valve 23' being normally open and the valve 64 being normally closed. Inthe heater 13 the emulsion may be highly heated by live steam in thecoil 29. The hot emulsion is.

then forced through the ipe 30 into one first of the plates 51preferably has no gas opening 53 so that all the emulsion passes throughthe opening 52. Since flowing liquids tend to travel in the shortestpath the emulsion then flows towards the extreme bottom of the notch inthe grounded electrode 50.

very concentrated electric field is 'formedvbetween the electrodes 42and 50 and of th notch of the grounded electrode 50,

one end of the are running up the live electrode 42 and the other endfollowing the plate 50 upwardly and outwardly. The po-- tential betweenthe electrodes 42 and 50 with no current flowing is determined by theratio between the primary and the.

secondary 71 and this potential is sufiicient to'cause a flow of currentthrough the emulsion. If such a flow occurs on one electrode 42 and noton the others the potential on that electrode is greatly lowered and theI if potential on each of the others is increased due to the seriesconnection of the primaries. This increase on the others results inanother arc forming from another electrode 42 to. electrode 50 and thisin turn raises the po tential still higher on the remaining two.

With disruptive currents flowing from three of the electrodes 42 it willbe found that. probably three times normal potential will exist from thefourth electrode 42 tov its co'rrises it gets longer and the potentialacross it, that is between a live electrode 42 and a grounded electrode50, increases until it is suflicient to establish a new are in thethroat when the long are above ceases. The space between the electrodes42 and 50 is then traversed by a succession of arcs each of which startsat the bottom of the electrode 42 and travels upwardly until it gets solong and unstable that a new are starts below. The current flowing ineach of the primaries 70 being the same due to their series connection,the current flowing between each pair of live and grounded electrodestends to persist and remain equal to the current flowing between eachother pair, the voltage between each pair varying-to suit the con-'ditions. I thus get a constant flow of current between each set ofelectrodes and a constant travel of the arcs through the body of theliquid being treated. This results in the rapid and completeagglomeration of water particles into large masses of free water leavingthe oil freefrom emuls1on.,

During the travel of the liquid through the heater 13 and the treater 14it is positively moved by the pump 12. The gas and vapor formed travelalong the top of the shell- 31 through the openings 53 and pass into thepipe 56-through the openings 57.

The flow of liquid 'is' along the bottom of the shell 31 through'theopenings 52. The pipe 56 extends to the bottom of the shell 31 so thatit collects and carries away any free water that settles in the bottomof the shell 31 before carrying away any oil. The accumulation of waterin the bottom of the shell 31 is thus prevented.

If desired the pump 12 may be used to. build up pressure in the heater13 and treater 14, the valve 58- being partially closed to control suchpressure. In practice I prefer, however, to omit the valve 58 pumpingagainst a static head due to the. fact that the pipe 56 enters the tank15 considerably below the surface of the oil therein.

Ordinarily the emulsion is pumped through the heater 13 into the treater14. The emulsion is broken in the treater 14 into free water and oilwhich pass into the tank 15 in which the water settles out and iswithdrawn through the pipe 61, the cleaned oil being-withdrawn throughthe pipe 60. In some cases in treating very stubborn emulsions I preferto close the valve 23, open the valve 64 and use the pump 16 tocirculate partially cleaned oil from the tank 15 through the heater 13and treater 14. When I have obtained a tank 15 full of clean oil, Istart the pump 12, open the valve 23 and regulate the valve 64 to supplya mixture of emulsion and partially cleaned oil to the treater 14. By sodiluting the emulsion with partially cleaned oil I can control thepercentage of moisture in the liquid in the treater 14 and thus handleemulsions of widely varying moisture content without adjustment of thevoltage applied or the shape of the electrode 50. I have also found thatby introducing into very fine emulsions, that is emulsions in which thewater is present in very fine particles, anemulsion in which large waterglobules are present that the work of dehydration is greatlyfacilitated. This I attribute tothe fact that where the-fine particlesonly are resent that paths are formed which are tru y conducting in theelectrolytic sense but which are of such high resistance that thecurrent density is very low and as a consequence these paths will carrycurrent indefinitely without disrupting. By mixing with the fineemulsion a very much coarser one the resistance of the path is verygreatly increased the current flow is also increased and the pathestablished is unstable.

Returning now to the objects of my invention as set forth in thepreamble to this specification it will be seen that since the heater 13and the treater 14 are closed vessels from which the air is excluded, Iam able to heat the liquid above' its boiling point and to subject it toViolent electrical discharges without danger of explosions due tocombination of the highly explosive gases so produced with oxygen.Moreover by making both theoutlet and inlet to the treater 14 and heater13 considerably ,higher than the topsof the treater 14 and heater 13 Iam able to insure the exclusion of air therefrom. Moreover bydischarging the liquid from the treater 14 at a pointconsiderablybelowthe surface of the treater liquid in the relatively cold tank 15 Iam able to condense any 1 gas carried in that liquid before it reachesthe surface. Also by providing the pipe 24 I am able to discharge anyair which may be delivered by the pump 12 to the pipe 22 so that it doesnot anter the heater 13.

Secondly it will be seen that by the construction of my apparatus I amable to maintain some pressure on the fluids in the heaters 13 and thetreater 14 so that gas formation is in a measure prevented.

Thirdly it will be seen that 'due to the shape of, the electrodes 42 andto the peculiar transformer connections used I am able to cause electricdischarges in even very stubborn emulsions and to maintain andreestablish such discharges when they cease for any reason.

F'ourthly, it will be seen that due to the small capacity of the treater14 and its construction I am able to quickly dispose of any water thatmay accidently get into the system. A

Fifthly, it will be seen that I have provided means in the pipe 62 andthe pump 16 for diluting the oil introduced so thatv its moisturecontent can be controlled.

I claim as my invention:

1. A process of dehydrating petroleum emulsions which comprises forcingthe emulsion under pressures in excess of atmospheric pressure through aconfined space frommy hand at Los Angeles, California, this 29 day ofJanuary,

. FORD W. HARRIS.

